I highly recommend Stonethwaite campsite, near Keswick.
Beautiful setting with a stream running through the campsite. Make sure you get the right one. Go into Stonethwaite village and go past Langstrath pub and follow the track. No showers though.
If you do stop here make sure you take a drive over Honister pass.
Excellent fell walking, climbing within walking distance of the camp, also canoe hire a 10 minute drive away.
In nearby Seathwaite you can rent a rod and catch Borrowdale trout or buy one at the cafe for about £2 that will have been caught and gutted
the same day.
Chapel Stile
Another good site in Langdale about 15 mins from Ambleside 10 mins from Hawkshead. Nice site with showers. Great walks and climbs 20mins walk from site.
Also stopped a couple of times at Eskdale campsite, that's good too, just behind the minature railway station. Access to this site is best reached by going over Hardknott pass(best in England) then through Boot. Lovely half hour drive to Wasdale and Wastwater.
Some excellent site on the banks of Ullswater too, great for saling too.
Hope this helps, sorry to ramble, once I get started on about the Lakes I just can't stop...